In light of the recent disclosure of vulnerabilities affecting Yealink IP phones, Carolina Digital Phone is committed to providing our customers with clear and concise information regarding the potential risks and the measures we have in place to mitigate them. Our built-in platform security features are designed to prevent issues from affecting our customers. We pride ourselves on our long-standing reputation for security and diligence in combating potential threats.
Understanding the Yealink IP Phone Vulnerabilities
Overview of CVE-2025-52916
Credit for the discovery of CVE-2025-52916 goes to Jeroen Hermans of CloudAware. He reported the vulnerability, involving brute-force enumeration of Yealink device serial numbers via the RPS platform, to CISA. This responsible disclosure enabled Yealink to address and mitigate the issue. No further details about the methodology or timeline of Hermans’ discovery are publicly specified in the available information.
CVE-2025-52916 identifies a bypass vulnerability affecting Yealink RPS (Redirect and Provisioning Service) before 2025-05-26. This vulnerability allows an attacker to bypass authentication mechanisms under specific conditions. There is a possibility, under these particular conditions, that unauthorized access to the redirect and provisioning service (RPS) could become possible. The affected products are Yealink IP phones that rely on the vulnerable Yealink RPS before the specified date. Carolina Digital Phone utilizes a multi-layered approach to security, including continuous monitoring for such vulnerabilities, and we are actively reviewing our systems.
Carolina Digital Phone constantly monitors advisories and the National Vulnerability Database to stay ahead of potential threats. Additionally, Carolina Digital Phone maintains a strict security protocol that does not allow public access to IP addresses. We take customer security seriously, and constantly monitor threats. To maintain this level of security, internal servers and settings are updated regularly.
Potential Impact of Unauthorized Access
If unprotected, the impact of unauthorized access due to this Yealink vulnerability could include several issues. One concern is the ability to redirect and provision devices to malicious servers, potentially compromising sensitive communications. Also, an attacker might leverage this bypass vulnerability to gain unauthorized OpenAPI access. The consequences of such access can be significant, including:
- Altering phone configurations.
- Intercepting calls.
- Gaining control of the Yealink IP phones themselves.
Carolina Digital Phone employs features such as rate limiting, verification attempt limits, and stringent certificate content validation to defend against these risks proactively.
National Vulnerability Database Advisory
Details of the Advisory and Disclosure
The National Vulnerability Database (NVD) has issued an advisory regarding the bypass vulnerability (CVE-2025-52916) affecting RPS before May 26, 2025. The disclosure details how an attacker could potentially bypass authentication mechanisms to gain unauthorized access. It is crucial for organizations using Yealink IP phones to understand the specifics of this advisory to assess their risk.
CVSS Scores and Severity Levels
The vulnerability CVSS score provides an assessment of the severity of CVE-2025-52916. While the specific score can vary, it’s important to note that even moderate scores can indicate a significant risk, especially if the vulnerability is easily exploitable. Carolina Digital Phone proactively monitors these CVSS scores and severity levels to prioritize our response and ensure appropriate measures to protect our customers from Yealink IP phone issues.
Mitigation Steps and Resolution Measures
Firmware Updates and Patches
Firmware updates and patches are critical in addressing the bypass vulnerability affecting Yealink IP phones. Applying the latest firmware released by Yealink Technical Support ensures that the vulnerability is addressed and that the affected systems are protected. If an updated firmware is required, Carolina Digital Phone will install the update to maintain the security of customer devices and mitigate potential risks from this vulnerability.
Access Control Measures in Yealink RPS
Implementing stringent access control measures within the Yealink RPS is vital to preventing unauthorized access and enumeration. Limiting OpenAPI access and enforcing strong authentication protocols can help prevent attackers from exploiting the bypass vulnerability. Carolina Digital Phone utilizes rate limiting and verification attempt limits to safeguard Yealink RPS against brute-force attacks.
Validating Certificate Content and Authentication
Thoroughly validating certificate content and strengthening authentication processes are essential to defend against unauthorized certificate uploads. Ensuring that the Yealink RPS properly validates certificate content can prevent malicious actors from exploiting the vulnerability. Carolina Digital Phone’s platform is designed to properly validate certificate content and authentication at every interface, minimizing risk.
Carolina Digital Phone’s Security Features
Built-in Platform Security for Yealink IP Phones
Carolina Digital Phone integrates robust security measures directly into our platform to protect Yealink IP phones. These measures mitigate risks such as the bypass vulnerability in Yealink RPS. By implementing rate limiting, verification attempt limits, and stringent certificate content verification, we significantly reduce the potential for unauthorized access and enumeration of enterprise accounts.
Long-standing Reputation for Security and Diligence
Carolina Digital Phone has a long-standing commitment to security, proactively monitoring for vulnerabilities and threats. We are diligent in applying necessary patches and updates to protect our customers from potential exploits. Our team continuously monitors advisories from the National Vulnerability Database and works closely with Yealink Technical Support to ensure the security of our cloud service> offerings.
Steps to Protect Enterprise Accounts
To safeguard enterprise accounts against potential threats, we implement multi-factor authentication and regularly audit access control. Carolina Digital Phone ensures that the Yealink RPS properly validates certificate content before allowing certificate uploads. SN verification steps are also taken to ensure an interface is secure. These steps minimize the risk of unauthorized OpenAPI access and protect customer data.
Carolina Digital Phone Security Checklist
- ✅ Encrypted communications – WSS over SSL/TLS, SIP over TLS, SRTP with DTLS
- ✅ User authentication – SSO, MFA
- ✅ Meeting security – Passwords, host management tools
- ✅ Secure storage & transfer – AWS, HTTPS, end-to-end encryption
- ✅ Private LAN hosting – No public Internet exposure
- ✅ Ongoing patching & updates – Continuous protection
- ✅ 24/7 monitoring – Suspicious activity detection
- ✅ Fraud prevention – Device passwords, suspicious IP blocking, STIR/SHAKEN
- ✅ HIPAA-compliant fax – No local storage of information
- ✅ Strong passwords – With password manager recommendations
Steps for Concerned Customers
Carolina Digital Phone is actively working to ensure that your Yealink IP phones have the latest firmware updates installed. If you have questions or concerns, contact Carolina Digital Phone’s support team for assistance with firmware updates or to address any questions you may have about the vulnerability. You can reach our support team by dialing 611 from your Carolina Digital Phone or by calling (336) 346-6000.
Encouraging Communication with Carolina Digital Phone
We encourage our customers with questions or concerns about the vulnerability to reach out to Carolina Digital Phone. Our team is available to provide detailed information about the vulnerability, our mitigation efforts, and best practices for securing your Yealink IP phone systems. We are committed to transparency and providing the support you need.
Resources for Additional Information
For additional information about the vulnerability, you can refer to the National Vulnerability Database advisory and the Yealink Technical Support website. Review the vulnerability summary provided by Jeroen Hermans, who initiated the disclosure of CVE-2025-52916. These resources provide detailed technical information about the vulnerability and recommended mitigation steps, including applying applicable firmware patches.
